Unmanned aerial vehicle (UAV) technology has proven to be a valuable tool for mission profiles involving intelligence, surveillance, reconnaissance, and payload delivery. In contexts such as low-altitude urban reconnaissance, a UAV such as a micro air vehicle (MAV) may encounter both large and small obstacles that may be fixed or moving, and whose position is not known in advance. There remains a need for improved autonomous vehicle navigation systems that can respond to varied and unknown obstacles in cluttered navigational environments.